Fine needle aspiration (FNA) and fine needle biopsy are diagnostic biopsy procedures used to obtain a sample from a target site in a patient body. A fine needle (e.g., 19-gauge to 25-gauge) is directed to a target site, and suction is applied to the proximal end of a lumen of the needle to aspirate cells through its distal end. The procedure typically is far less invasive than other biopsy techniques, whether performed percutaneously (e.g., to sample a suspected breast tumor or subcutaneous lesion) or endoscopically (e.g., to sample a suspected cholangiocarcinoma via a duodenoscope). Moreover, advances in endoscopic ultrasound (EUS) technology have helped physicians and patients by providing enhanced ability of a physician to visualize a biopsy needle to obtain a sample of material from a target site without requiring an open incision or use of large-bore needles and/or percutaneous trocars.
In order to provide desirable pushability and trackability for these small-bore sample-collection needles, and to prevent inadvertent (e.g., early and/or late) collection of tissue in one or more distal needle openings, a stylet is typically provided through the length of the needle lumen. After the distal end opening(s) of the needle is/are directed to a target location via a medical endoscope such as a duodenoscope or other minimally-invasive endoscope device, the stylet is withdrawn and a syringe or other modality is attached to the proximal needle end for generating vacuum through the needle lumen to facilitate sample collection by drawing sample material into the distal end opening(s) of the needle. Stylet-management may pose challenges during such procedures.
Specifically, a nurse or other person assisting the physician conducting the endoscopic sample collection must typically use both hands to withdraw the stylet from the needle lumen. Because the stylet may be nearly 2 meters in length and is non-sterile after having been inside the patient, it is usually wound up by nurse as it is withdrawn. However, the default configuration/orientation of existing stylets is generally straight, which is to say that their default configuration is to lie along an uncurved line in all longitudinal planes. As such, stylets are biased to become unwound. This can pose a sharps injury risk due to a sharp distal tip when a stylet springs loose from a wound-up position, and/or it can become contaminated by contacting other non-sterile surfaces. For this reason, the nurse must often clip or otherwise secure the wound-up stylet. In the event that the stylet must be reintroduced into the needle, both hands of the nurse are required to control unwinding and to feed the distal stylet portion back into the needle lumen. If the wound-up stylet escapes the clip or other constriction, it may contact the floor or another contaminating surface and have to be replaced by a sterile stylet—increasing procedure time and expense.
Thus, it may be desirable to provide a stylet configuration that will reduce procedure time, reduce the manual manipulation required during a stylet/needle procedure such as endoscopic sample collection (e.g., FNA, FNB), and that will reduce other risks associated with loss of stylet control during such a procedure.